In recent years, according to social demands and movements arising from energy and environmental issues, a fuel cell capable of being operated at room temperature to obtain high power density has been attracting attention as a power source for electric vehicles and as a stationary power source. A fuel cell is a clean power generation system whose byproduct generated by an electrode reaction is water in principle and whose load on the global environment is small. In particular, the polymer electrolyte fuel cell (PEFC) is anticipated to be a power source for electric vehicles because the PEFC is operated at a relatively low temperature.
The PEFC includes an electrolyte film, catalyst layers formed on both surfaces of the electrolyte film, and a Membrane Electrode Assembly (hereinafter, referred to as an MEA) having a gas diffusion layer (GDL) or the like. A fuel cell is formed of a plurality of MEAs being stacked on one another and sandwiched between separators.
In regard to MEA production, as a technology for forming electrode catalyst layers on both surfaces of an electrolyte film, a method of performing transfer printing on a catalyst layer formed on a catalyst transfer film to an electrolyte film from the catalyst transfer film (decal method, for example, see Japanese Unexamined Patent Application 2010-251012) is known. The catalyst transfer film can be produced by coating a base material such as a plastic film or the like with a catalyst and drying the coated film.
In a method disclosed in Japanese Unexamined Patent Application 2010-251012, a catalyst layer is transfer-printed on an electrolyte film by stacking catalyst transfer films respectively produced for an anode and a cathode on both surfaces of the electrolyte film such that the catalyst layer is in contact with the electrolyte film and then by performing heat pressing using a press machine.